Upper Jefferson River study presentation Jan. 27

The Montana Bureau of Mines and Geology (MBMG) Groundwater Investigation Program (GWIP) conducted a groundwater study in the Upper Jefferson Valley. This study was partly funded by Barrick Golden Sunlight Mine, and Madison and Jefferson Counties. On January 27, The MBMG will present an overview of the findings and recommendations from this study and will take questions. The presentations will be held from 5 p.m. to 7 p.m. at the Borden Conference Room, 103 West Legion, in Whitehall.

The purpose of the groundwater study was to investigate specific local groundwater issues. The study investigated two key issues: 1) effects to streams from existing and potential groundwater development; and 2) impacts to groundwater and surface water from land-use changes Irrigation activities supply water to the alluvial aquifer, which in turn discharges to surface water bodies and helps maintain river flows during the late season water shortages. If this important groundwater recharge source is drastically reduced, it could change the hydrologic system and reduce return flows that helps support the river during critically low flows.

With the completion of the upper Jefferson River Groundwater Investigation there now is definitive information on the potential impacts, and key areas of concern. The JRWC and its partners welcome the public's attendance and participation in this meeting as they begin to seek ways to address water recharge concerns.

In 2013, the Upper Jefferson River Groundwater Study was initiated by the Montana Bureau of Mines & Geology (MBMG). This study has now been completed. This study was conducted with matching funds provided by Barrick Golden Sunlight Mine, Madison and Jefferson Counties, and the willingness of Jefferson County landowners to participate in the study was key to its success.

The water resources of the upper Jefferson River valley fulfills many needs. Agriculture, the primary industry in the area, is dependent on adequate stream flow and groundwater yields. The entire population of the area is dependent on groundwater for their drinking water. The Jefferson River is also a popular fishing waterway. Due primarily to severe dewatering and elevated temperatures that occur during drought-year irrigation seasons, the Jefferson River has been subject to more stream closures than any other river in Montana and experiences depressed trout populations. The Montana Department of Fish, Wildlife and Parks has designated the Jefferson River, Pipestone Creek, and Whitetail Creek as Chronically Dewatered Streams

During the peak irrigation season (mid-July through mid-September), groundwater elevations continue to rise due to irrigation impacts, and surface water temperature and conductivity values show strong correlations with groundwater. During this critical time, groundwater, including irrigation return flows, are critical for maintaining late-summer stream flows.

Andy Bobst, Ginette Abdo and Ali Gerbil from the MBMG will present an overview of the Upper Jefferson groundwater study at the January 27th meeting. They will present their findings and recommendations, as well as take questions.

For more information please call Ted Dodge, 406-579-3762 or email Ted at ted.dodge516@gmail.com